Electronic power modules are used extensively for modifying readily available sources of electric power to suit specific applications. These modules are used in the manufacturing industry, in conventional and renewable power generation and transmission, and in automotive applications. Such modules may provide a direct current (DC) to DC function, a DC to alternating current (AC) function or an AC to AC function. These modules use solid-state devices, such as power semiconductor switches, typically insulated gate bipolar junction transistors (IGBTs), metal oxide semiconductor field effect transistors (MOSFETs), gate-turnoff thyristors (GTOs), and the like to achieve the required switching process. While the switches enable the transfer of great amounts of power, their control, essentially the turn on and turn off functions, is accomplished using very little energy through a gate terminal.
Electric motor drive systems as generally employed in electric vehicle applications typically include an AC electric motor, a power module and a DC power source, such as a storage battery. The power module typically converts the DC electric power from the power source to AC electric power to drive the electric motor and AC electric power from a power source to DC electric power for recharging the storage battery. The module may include IGBT or similar power semiconductor based switches that switch in a complementary manner to convert DC power to AC power and AC power to DC power, as the case may be. The AC power drives the AC electric motor, which in turn drives one or more wheels of the vehicle thereby providing propulsion, while the DC power is coupled to the storage battery system to replenish its charge.
The power semiconductor switches within the module operate at high switching speeds. At these switching speeds, the module is sensitive to electronic noise, and in particular noise resulting from induced or parasitic inductance. Operation at high switching speeds in combination with the power levels being processed furthermore generates significant heat often requiring cooling of the module to protect the components and to provide efficient operation.
Therefore, it is desirable to provide a package for the electronic components, and in particular the power semiconductor switches, of a module that reduces sensitivity to electronic noise and provides thermal management.